It is well-known that in shuttleless looms the filling thread is drawn from an outside source and inserted in the warp shed by flexible inserting members such as tapes or rapiers which are repeatedly wrapped about and extended from oscillating wheels by which they are driven. When the flexible tapes are being withdrawn from the warp shed they are wrapped tightly against the rim or outer periphery of their respective oscillating tape wheel; but when being unwrapped from the wheel and inserted into the shed, a guide means such as a tape restraining shoe is required to hold the tape radially inward and in close proximity to the rim of the wheel. The more common form of tape restraining shoe is an arcuate member made of a material such as wood, plastic, or metal. Each of the oscillating wheels has mounted on the frame thereof a plurality of tape restraining shoes which are circumferentially disposed about the outer periphery of the wheel. The inner arcuate surface of each shoe generally includes a wear and friction resistant sole for reducing friction as the flexible tape member is wound and unwound from the wheel at very high speeds.
The frictional heat created by the repeated oscillations of the wheel members and the movement of the tape against the outer surface of the tape shoe creates a condition called "bowing" of the flexible tapes. This lateral or transverse bowing condition is a serious detriment to the operation of the loom because it alters the intended position of the carrier members at the filling transfer point within the shed. When the condition is extreme and both tapes are caused to bow, perhaps in opposite directions, a more serious problem results whereby one carrier may fail to transfer the filling thread in synchronization with the receiving carrier; thus creating the possibility of a collision between the carriers that results in breakage thereof and the tearing or knotting of many of the warp threads. This problem has been recognized and a solution proposed in U.S. Pat. No. 3,323,555. The solution involves the provision of air ventilating ports in the housing adjacent the restraining shoes. While this approach has improved the bowing problem somewhat, other problems remain.
The frictional heat and excessive wear on the inner surface of the tape restraining shoe causes the wear resistant sole to soften and wear away to the extent that it increases the frictional drag on the tape members. In the past there has been no reasonable and efficient means for easily replacing these wear strips and most loom operators remove the entire tape restraining shoe, discard it, and replace it with a new shoe. The discarded shoe is either refurbished or discarded. This is obviously an expensive solution to the problem.
A still further problem with the tape restraining shoes has been the lack of a means for maintaining the wear strip of the shoe at a prescribed distance from the surface of the retractable tape. With known shoes there is only one position for mounting the shoe to the wheel frame and there has been no means for adjusting the position of the shoe to increase or decrease the distance between the surface of the wear strip and the flexible tape. Being able to make such an adjustment would significantly increase the life of the wear resistant material or surface on the shoe member.
It is to overcoming all of the above disadvantages by providing an improved tape restraining shoe that the present invention is directed. The invention is an improved tape restraining shoe having a means for mounting and positioning the shoe on the oscillating wheel frame such that the distance between the wear resistant surface of the shoe and the flexible inserting members can be adjusted; either at the time of initially mounting the shoe, or after the wear resistant sole has begun to wear away.
The adjustment means comprises a pair of elongated slots or apertures, spaced apart from each other, in the yoke portion of the shoe. The elongation of the apertures allows for incremental positioning of these apertures over those on the wheel supporting plate to which the shoes are attached. Once positioned, a fastener is inserted through the elongated aperture at any point and into the aperture on the wheel frame. The head of the nut or screwfastener, when tightened, will bias the shoe against the wheel supporting plate to hold the shoe securely in position. Additionally the arcuate undersurface of the improved shoe includes a groove or track means for receiving and releasably holding a replaceable wear strip therein such that an old strip can be simply removed and replaced with a new one without the necessity of discarding or refurbishing the entire shoe.
Further, the body portion of the improved tape restraining shoe is made from a heat conductive zinc aluminum alloy that will rapidly conduct heat away from the flexible inserting members and the replaceable wear resistant strip. The strip itself preferably is formed of Rulon.TM., a highly strong, heat absorbent material. By using such a material for forming the body of the tape restraining shoe to induce heat away from the flexible inserting members, the life of the inserting members is prolonged and there is a significant decrease in the likelihood of tape bowing.